This invention relates to a mode-locked solid-state laser in which its axial mode of oscillation is locked by means of an ultrasonic wave.
A laser apparatus is known which, as typically shown in Japanese Patent Application Unexamined Publication No. 61-208280, extracts part of light components at multiple wavelengths and that modulates the extracted component with an ultrasonic wave to achieve mode locking.
Most of the conventional ultrasonic-wave-modulated laser apparatus use a gas laser such as an argon laser tube. Further, the ultrasonic optical modulator is located between the output mirror and the laser oscillating tube, so that not only is the laser apparatus bulky and complex in composition but also it is difficult to achieve stable operation and complicated adjustments are needed.